1. Field of the Invention
This invention relates to an artificial knee joint, and more particularly to a multi-functional artificial knee joint that is suitable for fast and slow walking on sloping paths.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional artificial knee joint 200 is shown to include a linkage unit 81, a support frame 82 connected to a residual thigh 8 of a prosthesis wearer by the linkage unit 81, and a hydraulic device 83. The hydraulic device 83 includes a cylinder body 830, and a piston 831 disposed movably within the cylinder body 830 and connected to the linkage unit 81 so as to divide an interior space in the cylinder body 830 into upper and lower oil chambers 832, 833, which are communicated by an oil passage 834. When the thigh 8 is raised such that the joint 200 flexes to form an angle between the thigh 8 and a prosthetic lower leg 9, as shown in FIG. 1, the piston 831 moves from an upper limit position to a lower limit position.
When the lower leg 9 is aligned with the thigh 8 and is pressed against the ground by the thigh 8, as shown in FIG. 2, the piston 831 moves from the lower limit position to the upper limit position. Although the aforesaid conventional artificial knee joint can flex and extend, the lower leg 9 cannot provide a sufficient support to the thigh 8 during fast walking of the wearer or during walking of the wearer along a sloping path.